Innate and Acquired Resistance to Plasmodium Falciparum Malaria in Mali

December 14, 2019 updated by: National Institute of Allergy and Infectious Diseases (NIAID)

Studies of Innate and Acquired Resistance to P. Falciparum Malaria in Mali

This study, sponsored by NIAID and the University of Bamako, Mali, will identify genetic and other factors that may protect against severe malaria in some children.

Children between 6 months and 17 years of age who live in Kenieroba, Fourda or Bozokin villages in Mali may enroll in the study. Participants have a blood sample collected by finger prick with a small needle. The blood is examined for gene variants that influence the severity of disease in children exposed to the malaria parasite.

Children who develop a fever or other symptoms of malaria are evaluated and treated in Kenieroba s health center for up to 5 years from entering the study, or until they reach 18 years of age. The children are treated with artesunate and amodiaquine. Children with severe disease are treated with quinine. One tablespoon of blood is drawn from the children for study.

At the end of the dry season and the wet season, a subset of 200 healthy children are asked to provide 1 or 2 tablespoons of blood, drawn through a needle placed in a vein in the arm. Additional research blood samples may be requested from children between 2 and 17 years old. Blood will not be taken from any child more than twice a year.

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Study Overview

Status

Completed

Conditions

Detailed Description

Hemoglobin (Hb) and red blood cell (RBC) polymorphisms that give rise to HbS, HbC, alpha-thalassemia, G6PD-deficiency, and ABO blood groups occur at high frequency in Mali. To determine whether these Hb/RBC polymorphisms are associated with protection against mild malaria and malaria-associated anemia, we will conduct a cohort study in Mali. Approximately 1300 children will be genotyped for five Hb/RBC polymorphisms and followed for 5 years to compare mean incidence rates for mild malaria, stratified by polymorphism. Differences between Hb levels during acute malaria episodes and at baseline will be calculated to determine if Hb/RBC polymorphisms influence the degree of malaria-associated anemia. To investigate whether Hb/RBC polymorphisms impair monocyte activation, we will obtain parasites from children with malaria, culture them in RBCs of different genotype, and compare the parasitized RBCs for their ability to activate monocytes in vitro. Plasma samples from children with malaria will also be compared for their levels of monocyte-derived cytokines. A variety of single nucleotide polymorphisms (SNPs) in immune response genes have recently been identified in African populations. To determine whether these polymorphisms are associated with protection against severe malaria, we will compare the prevalence of SNPs in groups of children with severe or mild malaria. Blood Collection Study. Components of the innate immune system (e.g., Toll-like receptors) expressed on antigen presenting cells (APC) provide the first line of defense against microbial infection and frame the nature and scale of adaptive immune responses. To investigate whether APC from malaria-experienced individuals respond to TLR ligands in vitro stimulation assays, we will obtain blood samples from 100 healthy children in the dry season and again in the wet season. Immunological memory is a key feature of adaptive immunity and involves memory T cells. Clinical trials in which malaria-nafve human volunteers were vaccinated with merozoite MSP-1 antigens enabled us to study the development of immunological memory by measuring memory T cell cytokine production and expression of surface activation markers. To investigate whether memory T cells from malaria-experienced individuals respond similarly to AMA-I/MSP-1 ligands in vitro stimulation assays, we will obtain blood samples from an additional 100 healthy children in the dry season and again in the wet season. These collections of paired samples will enable us to explore the possibility that TLR- and AMA-1/MSP-l-induced immune responses are boosted during a transmission season and increase with age (a surrogate for disease controlling immunity).

Study Type

Observational

Enrollment (Actual)

1718

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Mali
      • Bamako, Mali
        • University of Bamako, Faculty of Medicine, Pharmacy and Odontostomatology

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

6 months to 65 years (Child, Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

  • INCLUSION CRITERIA:

(Cohort Study)

  • Resident of Kenieroba, Fourda, or Bozokin villages, and no plans to relocate away from the study village for the next 5 years.
  • Willingness to participate in the study as evidenced by informed consent of parents or guardians of children, and willingness to bring children to study clinic if they develop fever or other symptoms of malaria.
  • Age 6 months to 17 years.

(Blood Collection Study)

  • Children enrolled in the cohort study.
  • Willingness to participate in the study as evidenced by informed consent of parents or guardians of children.
  • Age 2 years to 14 years.
  • Hemoglobin level greater than or equal to 8.5g/dL.

(Parasite Clearance Study)

  • Children enrolled in the cohort study.
  • Willingness to participate in the study as evidenced by informed consent of parents or guardians of children.
  • Age 1 year to 17 years (inclusive).
  • P. falciparum density greater than or equal to 10,000/microL.
  • Present with their first episode of uncomplicated malaria of the 2010 transmission season or any episode during the 2012 transmission season.
  • Resident of Kenieroba

(Adult blood Collection Study)

  • Willingness to participate in the study as evidenced by informed consent.
  • Age 18 years to 65 years.
  • Hemoglobin level greater than or equal to 8.5 g/dL

EXCLUSION CRITERIA:

(Cohort Study)

  • Any condition that in the opinion of the investigator would render the subject unable to comply with the protocol (e.g., psychiatric disease).
  • Any health condition that in the opinion of the investigator would confound data analysis or pose unnecessary exposure risks to study personnel (e.g., individuals who are known to be HIV-infected or to have AIDS) or to the child (e.g., severe malnutrition).

(Blood Collection Study)

  • Any condition that in the opinion of the investigator would render the subject unable to comply with the protocol (e.g., psychiatric disease).
  • Any health condition that in the opinion of the investigator would confound data analysis or pose unnecessary exposure risks to study personnel (e.g., individuals who are known to be HIV-infected or to have AIDS) or to the child (e.g., severe malnutrition).

(Parasite Clearance Study)

  • Any condition that in the opinion of the investigator would render the subject unable to comply with the protocol (e.g., psychiatric diesase).
  • Any health condition that in the opinion of the investigator would confound data analysis or pose unnecessary exposure risks to study personnel (e.g., individuals who are known to be HIV-infected or to have AIDS) or to the child (e.g., severe malnutrition).
  • Pregnancy at the time of malaria episode.

(Adult Blood Collection Study)

  • Any condition that in the opinion of the investigator would render the subject unable to comply with the protocol (e.g., psychiatric disease)
  • Any health condition that in the opinion of the investigator would confound data analysis or pose unnecessary exposure risks to study personnel (e.g., individuals who are known to be HIV-infected or to have AIDS.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Institute of Allergy and Infectious Diseases (NIAID)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 21, 2008

Study Completion

November 19, 2013

Study Registration Dates

First Submitted

April 26, 2008

First Submitted That Met QC Criteria

April 28, 2008

First Posted (Estimate)

April 29, 2008

Study Record Updates

Last Update Posted (Actual)

December 17, 2019

Last Update Submitted That Met QC Criteria

December 14, 2019

Last Verified

November 19, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 999908120
  • 08-I-N120

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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